i saw a monk on facebook who claims to be ordained in theravada and zen
the impression i got is that he was theravada and then, without disrobing, ordained as a soto zen monk. From the Buddhist Monastic Code:

"The twelve equivalent pārājikas include the eleven disqualified types who should not be ordained as bhikkhus in the first place. If they happen to be ordained, their ordination is invalid; once they are found out they must be expelled for life (Mv.I.61-68; see BMC2, Chapter 14 for details). They are— ... a bhikkhu who has ordained in another religion without first giving up his status as a bhikkhu..." would it be fair to say zen and theravada are two different religions? or is religion a rougher translation of a more fine term

"Just as the ocean has a single taste — that of salt — in the same way, this Dhamma-Vinaya has a single taste: that of release."
— Ud 5.5

would it be fair to say zen and theravada are two different religions? or is religion a rougher translation of a more fine term

The rule that you cite is in the sacittaka class, meaning that culpability is contingent upon certain mental factors — knowledge, perception, intention, or some combination of these. It's not an acittaka rule where the mere act is an offence, regardless of what the bhikkhu knows, perceives or intends.

That being so, it's irrelevant whether Zen is actually inside or outside the Buddhasāsanā. If the bhikkhu perceives it as being inside, then he cannot be said to have the intention of ordaining outside.

That's not to say that the act wouldn't be blameworthy on other grounds; just not under the terms of this particular rule.

i saw a monk on facebook who claims to be ordained in theravada and zen
the impression i got is that he was theravada and then, without disrobing, ordained as a soto zen monk. From the Buddhist Monastic Code:

"The twelve equivalent pārājikas include the eleven disqualified types who should not be ordained as bhikkhus in the first place. If they happen to be ordained, their ordination is invalid; once they are found out they must be expelled for life (Mv.I.61-68; see BMC2, Chapter 14 for details). They are— ... a bhikkhu who has ordained in another religion without first giving up his status as a bhikkhu..." would it be fair to say zen and theravada are two different religions? or is religion a rougher translation of a more fine term

As an aside to your question, most Soto groups would care only if you met the requirements of Soto ordination, not what titles other groups gave you.

Technically speaking, it is more likely this person, if ordained at all, would have been ordained as a Soto priest as are most, if not all, ordinations in Japan. There are many degrees of priesthood. The distinction between “monk” and “priest” is also pretty vague in common language use and practice. There are also ceremonies for lay people, sometimes called “lay ordinations.” Additionally, there are Soto orders or sects that merge the role of “priest/monk/lay.” In practice, it all sorts out.

In both Soto and other forms of Buddhism, sadly, I have also seen several people buy a robe and claim to be “monks” or “priests” or even have authority to teach (even on Dhamma Wheel someone was trying to buy a robe so he could “self ordain” and roam around giving the public the impression that he was a monk). Some are badly confused or delusional; some are predators. This is why some Thai monk stores will sell only to monks or with a letter from a monastery.

would it be fair to say zen and theravada are two different religions?

They are theravada Buddhism and zen Buddhism. There is no religion of "theravada" and no religion of "zen". The religion is just "Buddhism". It would be a huge stretch to say they are different religions altogether.

When I was practicing at Shwe oo min I saw several Mahayana monks taking temporary (presumably just for the period of their stay) ordination in Theravada, mostly Vietnamese zen monks.

“Peace is within oneself to be found in the same place as agitation and suffering. It is not found in a forest or on a hilltop, nor is it given by a teacher. Where you experience suffering, you can also find freedom from suffering. Trying to run away from suffering is actually to run toward it.” ― Ajahn Chah

When I was practicing at Shwe oo min I saw several Mahayana monks taking temporary (presumably just for the period of their stay) ordination in Theravada, mostly Vietnamese zen monks.

There is or was also a monk exchange program berween Korea and Sri Lanka. I met a Sri Lankan Theravada monk at Song Kwang Sa (a major Zen training monastery in Korea) and Korean Zen monks and nuns in Sri Lanka at Theravada centers.

I believe Jack Kornfield tells the story of Ajahn Chah bringing a group of Western students to practice at a Korean Zen monastery famous for intensive practice. He had them all wear suits to impress the hosts that they were serious (not tourists, not casual visitors out for a thrill). It had the opposite effect. The Korean monks took one look at them and said they looked like fine gentlemen in their nice suits. They said Korean monks were not gentlemen, did not practice like gentlemen, and wondered if the nicely dressed Americans were up to hard training!

would it be fair to say zen and theravada are two different religions?

They are theravada Buddhism and zen Buddhism. There is no religion of "theravada" and no religion of "zen". The religion is just "Buddhism". It would be a huge stretch to say they are different religions altogether.

why in your opinion would it be a huge stretch?

"Just as the ocean has a single taste — that of salt — in the same way, this Dhamma-Vinaya has a single taste: that of release."
— Ud 5.5

not everyone, no. i have one particular bhikkhu in mind which also led me to make this post. not only that, but i've run into this many times, that everything that calling itself buddhist be rendered as such. i believe it is one's duty as a follower to point out apocrypha.

"Just as the ocean has a single taste — that of salt — in the same way, this Dhamma-Vinaya has a single taste: that of release."
— Ud 5.5

not everyone, no. i have one particular bhikkhu in mind which also led me to make this post. not only that, but i've run into this many times, that everything that calling itself buddhist be rendered as such. i believe it is one's duty as a follower to point out apocrypha.

Don’t know the particular person you refferred to or if he is really ordained in any tradition. As to the traditions themselves they are both Buddhist.

i believe he recently disrobed to take care of his parents but before that he was a theravada bhikkhu
unless i was lying, i don't see why i would need to name the bhikkhu/ex-bhikkhu. ""Religion" in this case would include different Dhammas, which Zen certainly qualifies as being. In the Buddha's day, the Buddha's dhamma and the dhamma of other sects would appear far more similar than different sects of Buddhism do today. Yet they were considered different "religions" (itself an imperfect translation of the different-dhamma concept)." does the burden of proof fall on me to prove zen and theravada are different religions of dhammas or does it fall on others to prove them the same.

"From the Buddhist Monastic Code:

"The twelve equivalent pārājikas include the eleven disqualified types who should not be ordained as bhikkhus in the first place. If they happen to be ordained, their ordination is invalid; once they are found out they must be expelled for life (Mv.I.61-68; see BMC2, Chapter 14 for details). They are— ... a bhikkhu who has ordained in another religion without first giving up his status as a bhikkhu...""

would it be topical for me to discuss wrong views in zen

"Just as the ocean has a single taste — that of salt — in the same way, this Dhamma-Vinaya has a single taste: that of release."
— Ud 5.5

i believe he recently disrobed to take care of his parents but before that he was a theravada bhikkhu
unless i was lying, i don't see why i would need to name the bhikkhu/ex-bhikkhu. ""Religion" in this case would include different Dhammas, which Zen certainly qualifies as being. In the Buddha's day, the Buddha's dhamma and the dhamma of other sects would appear far more similar than different sects of Buddhism do today. Yet they were considered different "religions" (itself an imperfect translation of the different-dhamma concept)." does the burden of proof fall on me to prove zen and theravada are different religions of dhammas or does it fall on others to prove them the same.

"From the Buddhist Monastic Code:

"The twelve equivalent pārājikas include the eleven disqualified types who should not be ordained as bhikkhus in the first place. If they happen to be ordained, their ordination is invalid; once they are found out they must be expelled for life (Mv.I.61-68; see BMC2, Chapter 14 for details). They are— ... a bhikkhu who has ordained in another religion without first giving up his status as a bhikkhu...""

would it be topical for me to discuss wrong views in zen

In case you feel insulted, no one is asking you to name the individual or accusing you of lying. For my part, I simply stated that I do not know the individual or his history, or what he may or may not have claimed or what validity such statements may have. However, I do know enough about Buddhism to recognize the various sects. The sects seem far more similar than different to me. I have no idea why someone would claim that the different groups in the Buddha’s time were more similar to each other than Buddhist sects are to each other today. It would fly in the face of the historical evidence we have (including the suttas). If you wish to make an extraordinary claim, it is indeed incumbent on you (if you care about your own intellectual integrity) to prove it or cease making the claim. That is your call. Your question about the monastic code has been answered by someone who shoukd know. He certainly knows more than me about that subject.

I am sure the non-Buddhist world sees all Buddhists as Buddhists. That isn't too surprising. But from a practical standpoint, there are major differences between theravada and mahayana. I believe Thanissaro Bhikkhu favors the term "Buddhist religions" to describe Buddhism at large to account for this. Hard for me personally how anybody could blend things in such a way. I know I tried to early on in my interest in Buddhism and it led to confusion.

oh yea, i did paste that twice
the difference to me is theravada was the only tradition that was good enough for me to convert
exposed to mahayana i remained an overly skeptical materialist
any way, i was pissed because on suttacentral my comment got reported for saying tibetan was not real buddhism. for me, it is the reliance on noncanonical content

"Just as the ocean has a single taste — that of salt — in the same way, this Dhamma-Vinaya has a single taste: that of release."
— Ud 5.5